- George Brent
- Tim Hanley
- Ilona Massey
- Carla Nillson
- Basil Rathbone
- Reggie Oliver
- Gene Lockhart
- Sidney Grenner
- George Zucco
- Webster
- Francis Pierlot
- Dr. Rowan
- Martin Kosleck
- Brunner
- Charles D. Brown
- Tetlow
- Marjorie Gateson
- Mrs. Grenner
- Leyland Hodgson
- Moulton
- Clayton Moore
- Sewell
- Gordon De Main
- Denby
- Frederick Worlock
- Sir Henry
- Bobby Barber
- Taxi Driver
- Trevor Bardette
- Krell, the Chemist
- Lynton Brent
- Agent
- Ralph Brooks
- Party Guest
- Frances Carson
- Undetermined Secondary Role
- John Dilson
- Decoding Expert
- Ralph Dunn
- Don
- Jay Eaton
- Restaurant Patron
- Antonio Filauri
- Porter
- Robert Fiske
- Headwaiter
- Bess Flowers
- Party Guest
- William Forrest
- Frank Cromwell, American Consul
- Jack Gardner
- Technician
- Martin Garralaga
- Lisbon Cab Driver
- Harold Goodwin
- Decoder on Piano
- Herschel Graham
- Club Patron
- Robert Haines
- Decoder
- Tom Hanlon
- Radio Announcer
- Sam Harris
- Man in Office
- Grace Hayle
- Weighty Dowager
- John Holland
- Scientist
- Selmer Jackson
- Colonel
- Marten Lamont
- Lt. Fenwick
- Leota Lorraine
- Party Guest
- Charles McAvoy
- New York Airport Guard
- Sam McDaniel
- Java
- Harold Miller
- Party Guest
- James Millican
- Roy
- Edmund Mortimer
- Party Guest
- Jack Mulhall
- Desk Clerk
- Lorraine Page
- Orchestra Leader
- Jack Perry
- Customs Officer
- Foster H. Phinney
- Club Patron
- Alexander Pollard
- Waiter
- Paul Power
- Club Patron
- Rita Quigley
- Letitia
- Otto Reichow
- German Radio Operator
- Ronald R. Rondell
- Party Guest
- Jeffrey Sayre
- Party Guest
- William Stack
- Waiter
- Wyndham Standing
- Secretary
- Larry Steers
- Hotel Guest
- Hans von Morhart
- Nazi
- Lillian Yarbo
- Prissy
